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CH08_Anderson 7/25/01 9:01 AM Page 208

208 CHAPTER EIGHT

Fig. 8.10. Fans of the NASA Ames 40 80 and 80 120 wind tunnels. (Photo
courtesy of NASA.)

In 1909, the Wright brothers standing in front of fan number three. The fans are 40 ft (12 m)
filed suit against Glenn Curtiss in diameter with 15 variable-pitch blades. Each motor is rated
for patent infringement. The at 12 megawatts (18,000 hp).
Wrights contended that Curtiss’ NASA Ames also has an 80 120 (24 36 m) open-circuit
use of ailerons was the same as wind tunnel. The truly impressive test section of this wind
wing warping. The lawsuit held tunnel is shown in Figure 8.11. Here winds from 0 to 100 mi/h
up development of aviation in (160 km/h) can be produced. Both the 40 80 and the 80 120
the United States until WWI. use the same fans shown in Figure 8.10. The tunnel can be
reconfigured with turning vanes to be either an open- or closed-
circuit tunnel. The original tunnel was the 40 80, but in the early
1980s a plan was put forth to create the 80 120. This major upgrade
allows for large wind-tunnel models to be tested in the 40 80 and full-
scale aircraft to be tested in the 80 120.
One thing to note about both open-circuit and closed-circuit wind
tunnels is that the test section is usually kept at atmospheric static
pressure. Significant pressures can build up in closed-circuit tunnels,